When I float the FX window of reaTune by double clicking the FX, the second click of the double click is interpreted by ReaTune as click in the ReaTune FX window, which moves the cursor.
This licecap shows what I mean (sorry for the size)
First I float the ReaTune FX window by using the menu. Then the cursor is not moved, it is initially at 0:56 and remains there in the floating FX window. But the second time I float the FX by double clicking, and then you can see that the second click, though it should have been "devoured" as part of the double click, is interpreted as a click in the ReaTune FX window, which then moves the cursor; the cursor ends up just before 0:44.
Just to be clear, there is only a single double click occurring, NOT a double click (to float the FX window) plus a single click in the floating FX window. And this behavior is consistent, it works the same every time.
This is extremely annoying, and it took me a long time to figure out why my cursor kept moving all over the place.